Oxidation resisting hydrocarbon products



Patented Mar. 13, 1951 OXIDATION RESISTING HYDROGARBQN PRODUCTS John P. McDermott, Roselle, N. 3., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application October .22, 1947,

.Serial No. 781,504

; v '5 Claims. (01. 252-4656) The present invention relates to the improvephosphonic acids. The organic groups of these merit of hydrocarbon products derived from peacids may be open chain radicals which may be .tltoleum sot-uces and more particularl to the long or short, straight or branched, saturated or preparation of improved mineral lubricating oil unsaturated, and may contain attachedsulfur or compositions by the incorporation therein of a 5 halogen atoms-or nitro groups. The organic-rad class-of additives which impart improved propi-cals may also be of an aromatic or aliphatic.- zerties to suchhydrocarbon compositions. aromatic character, and may consist of phenyl,

l-QInthe .;development of petroleum lubricating naphthyl or other ar-yl radicals which may con:- oils the trend has been to use more and more tain allcyl or other aliphaticside chains, and they efiicient refining methods in order to reduce the may consist of sulfurized aromatic groups. Oy-

iwndencyfof the oilsto form carbon and decloaliphatic groups are also included. As is well posits :of; solid matter or sludge. While such known, the organo-suhstituted thiop sphorous highlyrefinedoils possess many advantages, their and thiophosphoric acids may be readily premsistance to oxidation particularly under conpared by reacting alcohols, mercaptans, phenols rlitions of severe service is generally decreased or thiophenols with sulfides of phosphorus. The aandathey are .more prone to form soluble acidic corresponding thiophosphinic and th-iophosphon oxidation products which are corrosive. They "ic acids may be prepared by the Grignard reac are-:generallyless effective than the untreated oils tions, as illustrated by the following equations ,inrprotecting the metal surfaces which they con- (1) or anmthio hos hmic acid itact. against rusting and corrosion due to oxygen g p p randzzmoisture. They also often deposit thick RMgX+PCls- R:PC1 nil-ms of varnish on hot metal surfaces, such as R2PC1+KSHA R2PSH+KC1 .thepistons of internal combustion engines. 2) organmthiophosphonic acid:

1;. In accordance with the present invention a mew class of compounds has been discovered -l 2 SC1 Which when added to refined lubricating oils and -F G {Qthfil' petroleum hy ocarbon products in Small The organic acid halide employed in the reac proportions substantially reduce the tendency of t t form t mixed anhyd 'ide of the s- ':suc n;oils to corrode the m l Surfaces, p ent invention ma be any carboxylic acid halide 51113155 the Surfaces 0f Kip and cadmium having an organic group of the character of any sil-uel hearin s Which ialie ployed in internal or" the groups described in connection with the :combustion engin s, and y are k w e othiophosphoric,acidportionof the anhydridemptire-in nhi Oxidation of hydrocarbonpmdlecule. In general, the acid halides employed l ctssenerallymay have the compositions illustrated by. the 1 The new, classof materials which have been formulas 0001 RCSCL Where 7 is an found to p ss s the 11 d .stabilizlng or cyclic hydrocarbon g1'01 .p, which may contain properties described above are mixed anhydrides d sulfur or halogen atoms or nitro groups. deriv structurally from Gleam-Substituted "The new class or anti-oxidant materials of the anus of=phosphorus and organic carboxylic acids. presentinventicn may be more accurately, These anhydrides may be conveniently prepared 49 fined by the general formula "by'rea'cting a'm'e'tal salt of the acid of phosphorus with-an organic carboxylic acid chloride, as illustrated by the following type reaction: I ma): P\

Rom RCOCl Rom +1401 I SM s Wherein .R and .R are hydrocarbon tadicals which may or :may not have incorporated therein sulfur, halogens or nitro groups, X and Y are nth' above'formuias R-andR" representorgan- ...9xygen ,01 sulfur and 77, and 7 are ,0 ,qr l ini i ad and M represents wdicating that oxygen ,orsulfur may be present @ThB acids of Ph p Which y be .or absentin the positions indicated.

,yed in preparing the mixed anhydridesmaybe specific compounds useful for the purposes of ,g'ano-fsuhstitu'ted thiophosp'horous acids, .thio- ,the present invention may be. prepared by startjphosphor'ic acids, thiophosphinic acids and thio- "mg with materials having organic groups oi' n of 45 minutes (temp. C.).

character falling within the scope of the compounds described above. For example, in preparing the organo-substituted acids of phosphorous, whose metal salts are to be reacted with various acid halides, a large variety of alcohols and phenols may be employed as the original starting material. Illustrative of such materials are the monohydric' aliphatic alcohols, such as ethyl alcohol, isopropyl alcohol, tert.-butyl alcohol, lauryl alcohol, stearyl alcohol, wax alcohols, and alcohols obtained by the oxidation of petroleum hydrocarbons. Unsaturated alcohols, such as aleyl alcohol, and sulfurized alcohols, such as sulfurized oleyl alcohol, may be employed, as well as substituted alcohols containing halogens or nitro groups. Likewise, cyclic alcohols such as cyclohexyl alcohol may be employed. Among the phenols and naphthols may be mentioned the simple phenols as well as alkylated phenols and analogous naphthols and their derivatives and phenol sulfides formed by reacting phenols with sulfur halides.

The organic acid halides which may be employed in the preparation of the mixed anhydrides may be illustrated by any of the well known acid halides, such as acetyl chloride, stearyl chloride, benzoyl chloride, oleyl chloride, and analogous compounds. Thio-acid chlorides, in which sulfur replaces oxygen, illustrated by thioacetyl chloride, thiobenzoyl chloride, thiobutyryl chloride, and the like, may similarly be employed.

It is to be understood that not only single compounds such as metallic salts of single acids of phosphorus and single acid chlorides may be employed in the preparation of the anhydrides, butmixtures of salts and salts of mixed acids of phosphorus, as well as mixtures of acid chlorides may be employed in the preparation of anhydride products in accordance with the present invention. The products of reactions involving such mixtures will necessarily be mixtures of various anhydrides, but such anhydrides will fall within the general scope of the above definition.

For general antioxidant purposes and particularly when the additives are to be employed in mineral lubricating oils the amount of the addi- .tives will range from about 0.02% to about 3% .by weight, and when the additives are to be employed to improve the load carrying capacity of .a lubricant the amount will generally be somewhat greater, that is, of the order of 3% Ito'10% of additive.

@The preparation and testing of samples of the additives of the present invention are illustrated by the examples to be described in detail below, but such examples are not to be construed. as limiting the scope of the invention in any manner. 7

Example 1.Prepa1 ation of isopropyl thiophosphorz'o-benzoic ,anhydride To a stirred suspension of 47.2 g. of sodium isopropyl thiophosphate in 600cc. of benzenev contained in a 4-necked 2-liter flask equipped with a' stirrer, reflux condenser, dropping funnel and thermometer, was added a solution of 28.0 g.

of CsHsCOCl in 100 cc. of benzene over a period After heating for an additional 2 hours at C. the NaCl was filtered ofi and the benzene removed by vacuum sulfur.

Ezcample 2.Preparation of isoz'fiopyi thiophosphoric-acetic anhydride This preparation was carried out in the same manner as described in Example 1, using 47.2 g. of sodium isopropyl thiophosphate and 15.7 g. of CH3COC1. In this case, petroleum ether was used as the reaction medium and the final two hour heating period was conducted at 45 C. A clear dark red liquid was obtained containing 12.0% phosphorus and 23.2% sulfur.

Example 3.Preparation of octyl thiophosphoricacetic anhydride This preparation was carried out in the same manner as described in Example 2, using 78.4 g.

of potassium octyl thiophosphate (prepared from 2-ethylhexanol) and 15.7 g. of CH3COC1. A clear pale yellow liquid was obtained containing 7.5% phosphorus and 15.3% sulfur.

Example 4.Laboratory bearing corrosion test.

Blends containing 0.25% each of the products of Examples 1 to 3 in a paraflinic type mineral lubricating oil of SAE-20 grade .and a sample of the unblended base oil were submitted to a laboratory test designed to measure the efiectiveness of the products in inhibiting the corrosiveness of a typical mineral lubricating oil toward the surfaces of copper lead bearings. The test was conducted as follows: 500 cc. of the oil was placed in a glass oxidation tube (13 inches long and 2% inches in diameter) fitted at the bottom with a inch air inlet tube perforated to facilitate air distribution. The oxidation tube was then immersed in a heating bath so that the oil temperature was maintained at 825 F. during the test. Two quarter sectionsof automotive bearings of copperlead alloy of known weight having a total area. of 25 sq. cm. were attached to opposite sides of a stainless steel rod which was then immersed in the test oil and rotated at 600 R. P. M., thus providing suihcient agitation of the sample during the test. Air was then blown through the oil at the rate of 2 cu. ft. per hour. At the end of each 4-hour period the hearings were removed, washed with naphtha and weighed to determine the amount of loss by corrosion. The bearings were then repolished (to increase the severity of the test), reweighed, and then subjected to the test for additional 4-hour periods in like manner. The results are given in the following table as corrosion life, which indicates the number of hours required for the bearings to lose mg. in weight, determined by interpolation of the data obtained in the various periods.

Example 5.-Lauson engine tests Blends containing 0.75% each of the products of Examples 1 and 2 in a solvent extracted Mid- Continent lubricating oil of SAE-lO grade and a sample of the unblended base oil were employed as crankcase lubricants in tests with a Lauson engine operated at 300 F. jacket temperature, 295 F. oil temperature. 1800 R. P. M. speed and 1.5 indicated kilowatt load, the tests being conducted for 20 hours each. The loss in weight of thecopper-lead bearing was determined in each test. The results are as follows:

Beariillg Weight Oil Blend oss (Mg/B caring) The products of the present invention may be employed not only in ordinary hydrocarbon lubrieating oils but also in the heavy duty type of lubricating oils which have been compounded with such detergent type additives as metal soaps, metal petroleum sulfonates, metal phenates, metal alcoholates, metal alkyl phenol sulfides, metal organo phosphates, thiophosphates, phosphites and thiophosphites, metal salicylates, metal xanthates and thioxanthates, metal thiocarbamates, amines and amine derivatives, reaction products of metal phenates and sulfur, reaction products of metal phenates and phosphorus sulfides, metal phenol sulfonates, and the like. Thus the additives of the present invention may be used in lubricating oils containing such other addition agents as barium tert.-octylphenol sulfide, calcium tert.-amylphenol sulfide, nickel oleate, barium octadecylate, calcium phenyl stearate, zinc diisopropyl salicylate, aluminum naphthenate, calcium cetyl phosphate, barium di-tert.- amylphenol sulfide, calcium petroleum sulfonate, zinc methylcyclohexyl thiophosphate, calcium dichlorostearate, etc. Other types of additives, such as phenols and phenol sulfides, may be employed.

The lubricating oil base stocks used in the compositions of this invention may be straight mineral lubricating oils or distillates derived from parafiim'c, naphthenic, asphaltic or mixed base crudes, or, if desired, various blended oils may be employed as well as residuals, particularly those from which asphaltic constituents have been carefully removed. The oils may be refined by conventional methods using acid, alkali and/ or clay or other agents such as aluminum chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents of the type of phenol, sulfur dioxide, furfural, dichlorodiethyl ether, nitrobenzene, crotonaldehyde, etc. Hydrogenated oils or white oils may be employed as well as synthetic oils prepared, for example, by the polymerization of olefins or by the reaction of oxides of carbon with hydrogen or by the hydrogenation of coal or its products. In certain instances cracking coil tar fractions and coal tar or shale oil distillates may also be used. Also, for special applications, animal, vegetable or fish oils or their hydrogenated or voltolized products may be employed in admixture with mineral oils.

For the best results the base stock chosen should normally be that oil which without the new additive present gives the optimum performance in the service contemplated. However, since one advantage of the additives is that their use also makes feasible the employment of less satisfactory mineral oils or other oils, no strict rule can be laid down for the choice of the base stock. Certain essentials must of course be observed. The oil must possess the viscosity and volatility characteristics known to be required for the service contemplated. The oil must be a satisfactory solvent for the additive, although in some cases auxiliary solvent agents may be used. The lubricating oils, however they may have been produced, may vary considerably in viscosity and other properties depending upon the particular use for which they are desired, but they usually range from about 40 to 150 seconds Saybolt viscosity at 210 F. For the lubricating of certain low and medium speed Diesel engines the general practice has often been to use a lubricating 011 base stock prepared from naphthenic or aromatic crudes and having a Saybolt viscosity at 210 F. of 45 to seconds and a viscosity index of 0 to 50. However, in certain types of Diesel engine and other gasoline engine service, oils of higher viscosity index are often preferred, for example, up to '75 to 100, or even higher, viscosity index.

In addition to the material to be added according to the present invention, other agents may also be used such as dyes, pour depressors, heat thickened fatty oils, sulfurized fatty oils, organometallic compounds, metallic or other soaps, sludge dispersers, antioxidants, thickeners, viscosity index improvers, oiliness agents, resins, rubber, olefin polymers, voltolized fats, voltolized mineral oils, and/or voltolized Waxes, and colloidal solids such as graphite or zinc oxide, etc. Solvents and assisting agents, such as esters, ketones, alcohols, aldehydes, halogenated or nitrated compounds, and the like may also be employed. "m

Assisting agents which are particularly desirable as plasticizers and defoamers are the higher alcohols having eight or more carbon atoms and preferably 12 to 20 carbon atoms. The alcohols may be saturated straight or branched chain aliphatic alcohols such as octyl alcohol (CaHmOI-I) lauryl alcohol (C12H25OH), cetyl alcohol stearyl alcohol, sometimes referred to as octadecyl alcohol (CmHsvOI-I) heptadecyl alcohol (CrrI-IssOH) and the like; the corresponding olefinic alcohols such as oleyl alcohol; cyclic alcohols such as naphthenic alcohols; and aryl substituted alkyl alcohols, for instance, phenyl octyl alcohol, or octadecyl benzyl alcohol; or mixtures of these various alcohols, which may be pure or substantially pure synthetic alcohols. One may also use mixed naturally occurring alcohols such as those found in wool fat (which is known to contain a substantial percentage of alcohols having about 16 to 18 carbon atoms) and in sperm oil (which contains a high percentage of cetyl alcohol); and although it is preferable to isolate the alcohols from those materials, for some purposes the wool fat, sperm oil or other natural products rich in alcohols may be used per se. Products prepared synthetically by chemical processes may also be used, such as alcohols prepared by the oxidation of petroleum hydrocarbons, e. g., paraifin wax, petrolatum, etc.

In addition to being employed in crankcase lubricants the additives of the present invention may also be used in extreme pressure lubricants, engine flushing oils, industrial oils, general machinery oils, process oils, rust preventive compositions, and greases.

The additives of the present invention may be employed as antioxidant or stabilizing agents not only in mineral lubricating oils, but also in hydrocarbon products generally, where improved resistance to oxidation is desired. Thus the products may be added to motor oils. Diesel fuels,

R'CO

wherein R is an alkyl radical and R is a radical selected from the class consisting of alkyl and phenyl radicals.

- 2. A composition according to claim 1 in which the petroleum hydrocarbon product is a lubricating oil fraction.

3. A composition according to claim 1 in which R is an isopropyl radical and R is a phenyl radical.

4. A composition according to claim 1 in which R is an isopropyl radical and R is a methyl radical.

5. A composition according to claim 1 in which R is an octyl radical and R is a methyl radical.

JOHN P. MCDERMOTT.

REFERENCES CITED The followine references are of record in the file of this patent:

V UNITED STATES PATENTS Number Name Date 1,949,629 Romieux Mar. 6, 1934 2,063,629 Salzberg Dec. 8, 1936 2,198,514 MacAfee Apr. 30, 1940 2,226,420 Badertscher Dec. 24, 1940 2,266,514 Romieux Dec. 16, 1941 2,354,536 Nelson July 25, 1944 

1. A COMPOSITION CONSISTING ESSENTIALLY OF A PETROLEUM HYDROCARBON PRODUCT HAVING INCORPORATED THEREIN 0.02% TO 10% OF A MIXED ACID ANHYDRIDE OF THE FORMULA- 